World War II ended 70 years ago - here's the planned US invasion of Japan that never happened

On August 14, 1945, American President Henry Truman announced the unconditional surrender of Japan's Emperor Hirohito, thereby ending the second world war.

The surrender came after months of bombing raids across the Japanese countryside, two atomic bombs, and Russia's declaration of war on the island nation.

The iron resolve of the Japanese was a big factor in the US' planned invasion of mainland Japan. The culture known for literally putting death before dishonor with practices like hari-kiri would not, by any stretch of the imagination, go softly into surrender.

By the time the first atomic bomb was dropped on Hiroshima, already 500,000 Japanese had died during bombing raids, not just in Tokyo, but in smaller towns too.

This badly hurt Japanese morale as Yutaka Akabane, a senior level civil servant, observed: "It was the raids on the medium and smaller cities which had the worst effect and really brought home to the people the experience of bombing and a demoralization of faith in the outcome of the war."

But despite several bombing raids a week in the beginning of 1945, and the resulting displacement of 5,000,000 people, the Japanese remained resolute.

And as US forces prepared a ground invasion, they were acutely aware of the challenges they faced against an iron-willed Japanese population. 

The planning committee for the US invasion expected that "operations in this area will be opposed not only by the available organized military forces of the Empire, but also by a fanatically hostile population."

Nevertheless, the Allied forces prepared to send 42 aircraft carriers, 24 battleships, and 400 destroyer ships and escorts to Japan's coast. The Allies expected 456,000 deaths in the invasion of Japan's military stronghold at Kyushu alone.

In preparation for what everyone expected to be a bloody, prolonged clash, the US government manufactured 500,000 purple hearts to be awarded to soldiers wounded in the invasion.

At the same time 32 million Japanese braced for war. That figure includes all men between the ages of 15 and 60, and all women between 17 and 45. They would fight until the last man, bearing whatever weapons they could muster, from bamboo spears, to antique cannons, to machine guns.

Even children had been trained to act as suicide bombers, strapping explosives to themselves and rolling under Allied tank treads.

But on July 16, 1945, the US secretly and successfully carried out the world's first atomic bomb detonation, giving the US another option in the war against Japan. 

After the atomic bombing of Hiroshima, on August 8, the USSR then declared war on Japan as well, and on the next day they attacked Japanese occupied Manchuria, China. On that same day, another bomb was dropped on Nagasaki.

Japan had previously been presented the Potsdam Declaration, or terms for an unconditional surrender, but they had refused it.

Even after the two atomic bombs, Japan would not surrender for fear of how Emperor Hirohito would be treated after the war.

Emperor Hirohito, was not merely a constitutional monarch, but a living god in the eyes of the Japanese. They would not see him treated as a war criminal by Allied forces, and after Pearl Harbor, the 60,000 western allied lives lost in the pacific theater, and 20 million or so Asian lives lost to Japanese imperialism, the Allies would accept nothing less than an unconditional surrender.

Japan and the Allies spent mid-August arguing over the exact language of the surrender, but on August 15, Emperor Hirohito addressed his nation via radio for the first time ever to announce his surrender. Due to a difference in time zones, this anniversary is remembered on the August 14 in the US.

Just last month, Japan officially released the master audio recording of Hirohito's surrender. A version of this recording can be heard below: